Historically, one of the major disadvantages in the use of hydraulic elevators has been the noise and vibration generated by the rapid flow of fluid under pressure throughout the hydraulic system. As a result, elevator manufacturers are required to install muffling devices into the hydraulic system to reduce the fluid flow noise and vibration.
Muffler systems historically utilized with hydraulic elevators have consisted of complex devices for diverting the flow of fluid to thereby reduce the flow noise. Such devices have failed to alleviate the noise and vibration problems and have been costly to manufacture, thereby resulting in higher elevator costs.
The present invention overcomes the above and other problems associated with the prior art. The muffler and method of manufacturing the muffler of the present invention result in an effective and cost efficient apparatus for splitting the flow of fluid in a hydraulic system to reduce the fluid noise and vibration. The muffler includes a housing for a cast urethane insert having two different sized flow ports extending longitudinally through the insert for splitting the flow of fluid as it enters the housing. The housing is substantially larger in diameter than the fluid path of the hydraulic system and includes adapters for connecting to the system fluid lines. Embedded within the urethane insert are hollow chambers extending parallel to the flow ports for absorbing the vibration and sound waves traveling through the fluid as it flows under pressure through the system. Additionally, the urethane insert includes 40 percent microspheres, resulting in a urethane product that is 40 percent air by volume to further increase absorption of the vibration and sound waves traveling through the fluid.
In the manufacturing process the microspheres are created by adding hollow glass spheres to the urethane prepolymer prior to casting the urethane insert. Thus, the microspheres created by the glass spheres not only act as filler to reduce the amount of urethane used in the insert, but also act as additional vibration and sound absorption cavities within the insert, thereby increasing the effectiveness and reducing the cost of the muffler, and, thus, the cost of the elevator.